使用printf时，行未正确对齐

Question

我正在尝试使用printf打印BASH脚本中的行。我知道"%60s“会对齐文本，但出于某种原因，我得到了以下输出：

Welcome root! Please select an option:

                         [1] Install startup repos
                           [2] Update sources.list
                             [3] Edit sources.list
                            [4] Reset sources.list

下面是我的脚本：

   function main () {
       main_header
       printf "%20s\n"  "${YELLOW}Welcome ${USER}! Please select an option:"
       printf "%60s\n"  "${GREEN}[1] ${YELLOW}Install new sources.list"
       printf "%60s\n"  "${GREEN}[2] ${YELLOW}Update sources.list"
       printf "%60s\n"  "${GREEN}[3] ${YELLOW}Edit sources.list"
       printf "%60s\n"  "${GREEN}[4] ${YELLOW}Reset sources.list"
    }

    main

有谁有什么想法吗？

Answer 1

这些是对齐的:每行都是60个字符的长度，向右对齐。尝试使用"%-60s“来向左对齐。

Answer 2

对我来说，它打印出来是正确对齐的。要将其左对齐，请使用%-，例如：

function main () {
   main_header
   printf "%-20s\n"  "${YELLOW}Welcome ${USER}! Please select an option:"
   printf "%-60s\n"  "${GREEN}[1] ${YELLOW}Install new sources.list"
   printf "%-60s\n"  "${GREEN}[2] ${YELLOW}Update sources.list"
   printf "%-60s\n"  "${GREEN}[3] ${YELLOW}Edit sources.list"
   printf "%-60s\n"  "${GREEN}[4] ${YELLOW}Reset sources.list"
}

这是打印

Welcome ! Please select an option:
[1] Install new sources.list
[2] Update sources.list
[3] Edit sources.list
[4] Reset sources.list

(不包括有关main_header的错误消息:找不到命令)

要对齐“请”下的后续行，请确定缩进的长度，使用按该长度缩进的格式字符串创建一个变量，并在要缩进的行的printf语句中使用该格式字符串。格式化字符串的诀窍是，它首先写入一个空字符串，以获得与字段宽度相等的缩进，然后在同一行上写入您想要的字符串。例如,

indentString="${YELLOW}Welcome ${USER}! "
indentLength=${#indentString}
indentFormat="%${indentLength}s%s\n"
printf "$indentFormat" "" "${GREEN}[1] ${YELLOW}Install new sources.list"

把它放到main()中，它就变成了：

function main () {
   indentString="${YELLOW}Welcome ${USER}! "
   indentLength=${#indentString}
   indentFormat="%${indentLength}s%s\n"
   main_header
   printf "%-20s\n" "${YELLOW}Welcome ${USER}! Please select an option:"
   printf "$indentFormat" "" "${GREEN}[1] ${YELLOW}Install new sources.list"
   printf "$indentFormat" "" "${GREEN}[2] ${YELLOW}Update sources.list"
   printf "$indentFormat" "" "${GREEN}[3] ${YELLOW}Edit sources.list"
   printf "$indentFormat" "" "${GREEN}[4] ${YELLOW}Reset sources.list"
}

打印的内容：

Welcome training! Please select an option:
                  [1] Install new sources.list
                  [2] Update sources.list
                  [3] Edit sources.list
                  [4] Reset sources.list

Answer 3

我喜欢用pr缩进。有时我会使用remote_function | tr -pro 3来清楚地查看远程输出。

在您的示例中，使用pr将生成以下代码：

function options () {
        echo "${GREEN}[1] ${YELLOW}Install new sources.list"
        echo "${GREEN}[2] ${YELLOW}Update sources.list"
        echo "${GREEN}[3] ${YELLOW}Edit sources.list"
        echo "${GREEN}[4] ${YELLOW}Reset sources.list"
}

function main () {
        printf "%20s\n"  "${YELLOW}Welcome ${USER}! Please select an option:"
        options | pr -tro 17
}

main